//float width,float height 设计分辨率

//resolutionPolicy 适配策略  这里用kResolutionFixedHeight：高度固定

void CCEGLViewProtocol::setDesignResolutionSize(float width,float height,ResolutionPolicy resolutionPolicy)
{
    CCAssert(resolutionPolicy != kResolutionUnKnown,"should set resolutionPolicy");
    
    if (width == 0.0f || height == 0.0f)
    {
        return;
    }

    //设置设计分辨率
    m_obDesignResolutionSize.setSize(width,height);
    
    //计算缩放比率  m_obScreenSize(屏幕大小)
    m_fScaleX = (float)m_obScreenSize.width / m_obDesignResolutionSize.width;
    m_fScaleY = (float)m_obScreenSize.height / m_obDesignResolutionSize.height;
    
    if (resolutionPolicy == kResolutionNoBorder)
    {
        m_fScaleX = m_fScaleY = MAX(m_fScaleX,m_fScaleY);
    }
    
    if (resolutionPolicy == kResolutionShowAll)
    {
        m_fScaleX = m_fScaleY = MIN(m_fScaleX,m_fScaleY);
    }

    //我们这里使用的，高度固定的意思，就是高度的缩放比例固定，根据高度缩放比率计算宽度
    //这里会根据我们设置的设计分辨率，然后根据适配策略，调整设计分辨率
    if ( resolutionPolicy == kResolutionFixedHeight) {
    	m_fScaleX = m_fScaleY;
    	m_obDesignResolutionSize.width = ceilf(m_obScreenSize.width/m_fScaleX);
    }

    if ( resolutionPolicy == kResolutionFixedWidth) {
    	m_fScaleY = m_fScaleX;
    	m_obDesignResolutionSize.height = ceilf(m_obScreenSize.height/m_fScaleY);
    }

    // calculate the rect of viewport    
    float viewPortW = m_obDesignResolutionSize.width * m_fScaleX;
    float viewPortH = m_obDesignResolutionSize.height * m_fScaleY;

    m_obViewPortRect.setRect((m_obScreenSize.width - viewPortW) / 2,(m_obScreenSize.height - viewPortH) / 2,viewPortW,viewPortH);
    
    m_eResolutionPolicy = resolutionPolicy;
    
	// reset director's member variables to fit visible rect
	//下面说明：
    CCDirector::sharedDirector()->m_obWinSizeInPoints = getDesignResolutionSize();
    CCDirector::sharedDirector()->createStatsLabel();
    CCDirector::sharedDirector()->setGLDefaultValues();
}

通过这句赋值：

 m_obWinSizeInPoints = m_pobOpenGLView->getDesignResolutionSize();

我们平时使用的接口，获取winSize:

CCSize CCDirector::getWinSize(void)
{
  return m_obWinSizeInPoints;
}

举例：

小米2s 720*1280

设计分辨率 640*960

固定高度,缩放比率：

720/640 = 1.125

计算宽度为：1280/1.125 = 1138

由此得到我们的winSize为：640*1138

通过打印信息得到：

03-16 20:49:22.579: D/cocos2d-x debug info(8833): [LUA-print] =====winSize  width=====1138
03-16 20:49:22.579: D/cocos2d-x debug info(8833): [LUA-print] =====winSize  height=====640